BR102014031848B1 - DEVICE FOR SUPPLYING DIFFERENT LOADS FROM AN ELECTRIC POWER SUPPLY NETWORK - Google Patents

Abstract

modular and reconfigurable electrical power conversion device. the invention refers to a device for supplying various loads (14) from an electrical energy supply network (25), comprising several converters (16), fed into electrical energy by the network (25), ensuring conversion and supplying electrical energy to at least one load (14). the device comprises a control organ (17) that allows several converters (16) to be associated in parallel to supply at least one load (14), in response to a power need of at least one load (14). each of the converters (16) comprises distributed means (33) for limiting the recirculation currents generated by the parallel association of several converters (16).

Description

[001] The invention refers to a modular and reconfigurable power supply device for several loads from an electrical energy supply network. More precisely, it refers to an electrical supply device for aircraft capable of limiting the recirculation currents generated when paralleling converters dedicated to supplying the same load.

[002] Larger aircraft have more and more built-in electrical equipment. These equipments are of a very varied nature and their electrical consumption is quite variable over time. For example, aircraft flight controls, internal climate control and lighting systems work almost continuously while engine start systems, electrical braking systems or redundant safety systems such as control commands , are only used for short durations during a mission.

[003] Generally, the aircraft has a three-phase electrical energy supply network allowing the supply of all electrical equipment, hereinafter referred to as loads. Different loads may require different energy inputs in voltage and type of current, alternating or direct. For example, loads can be more or less tolerant to variations in the electrical network that feeds them. In most power supply systems currently built into the aircraft, each load is associated with its own converter and its own dedicated filtration network. An attempt was made to implement a more modular power supply structure, allowing to dynamically distribute one or several converters to electrical loads depending on their power needs. It is known in particular from the applicant, the patent application published under the reference FR0603002 describing the principle of a modular electrical supply device. Figure 1 of the present application illustrates the principle of such a modular electrical architecture. An electrical power supply network 10 comprises, for example, several electrical generators 11 on board the aircraft. The network can also comprise electric energy storage batteries. It may also comprise means of connection to a ground power supply network, allowing power supply to the aircraft parked on a runway. The electrical energy supply network 10 comprises conversion 12 and filtering 13 means allowing the execution of the electrical signal generated by the generators 11 and transmitted to the on-board network. This electrical power supply network allows the supply of various loads 14. It can include ECS HVAC systems, Anglo-Saxon acronym for Environmental Control Systems, MES engine starter systems, Anglo-Saxon acronym for Main Engine Start, or hydraulic pumps EMP, Anglo-Saxon acronym for Electro Mechanical Pump, used, for example, for flight control command.

[004] Between the electric power supply network 10 and the various loads 14, a modular power supply device 15 aims to allocate in real time to each load one or more converters 16 depending on the load's power needs. It aims to combine several converters 16 in parallel, allowing to supply the necessary power level for a load 14. The paralleling of converters 16, by a control unit-controlled real-time allocation, to the different loads 14, allows to optimize the power built-in conversion and thus limit the weight and cost of the conversion elements. In order to reduce electrical noise and be able to comply with the requirements of EMI, the Anglo-Saxon acronym for Electro Magnetic Interference, we resorted to the filtering and interleaving techniques of the associated converters in parallel. The interleaving of signals from two converters in parallel is illustrated in figure 2. The filtering integrated in the converters is optimized by real-time interleaving both at input 20 of converters 16, next to the power supply network 10, and at output 21 of the converters 16, next to the electrical load 14. The cut-off frequency and the type of cycle-ratio opening command, or PWM, can also be adapted in real time to optimize the size and weights of the filters.

[005] The execution of a modular and reconfigurable power supply device is based, therefore, on the ability to dynamically parallelize and interlace several converters. Therefore, placing in parallel and/or interlacing is oriented towards difficulties related mainly to the generation of recirculation currents between the converters. These recirculation currents significantly increase the total current perceived by the active components of the converters. To withstand these high currents, a major oversizing of the components becomes necessary. The adaptation of the converters to the recirculation currents through an appropriate dimensioning of the active components (in the thermal, electrical, EMI plane) is, in practice, little carried out; the weights, volume and cost of such a converter being unadapted.

[006] To overcome the difficulties presented by the generation of recirculation currents, a visualized solution is to run between the associated converters in parallel an interphase inductance, also called an interphase inductor. Figure 3 illustrates the principle of using an interphase inductor for the parallel combination of two converters. In this example, two converters 16 are powered in parallel by the same electrical source 25. The outputs 21 of the two converters are reconnected to an interphase inductor 26. The interface inductor 26 gathers the signals of the outputs 21 of the converters 16 into a signal of output 27. The association of two converters 16 in parallel generates recirculation currents represented and referenced as iz in figure 3. The interphase inductor 26 is used to generate an important zero sequence impedance allowing to reduce the recirculation currents, in particular the currents of high frequency recirculation. This solution consists of connecting one to one each of the three phases of the two converters through an interphase inductor. This solution effectively limits the recirculation currents, but its main inconvenience is to add an element between the converters. For a complex power supply architecture, running a large number of sources and electrical loads, it is necessary to add more interphase inductors than the considered combinations of converters. In addition, the filtration represented by module 28 in figure 3 must be performed at the output of the interphase inductor. In other words, the addition of an interphase inductor between the converters implies the execution of a centralized filtration system, not distributed inside each of the converters. The resource for an interphase inductor and therefore for a centralized filtering, for the combination of converters considered, limits the modularity of the architecture. It is possible to switch only statically, between the pre-defined settings, imposed by the structure of the interphase inductors. The number and mass of interphase inducers can become significant and in practice limits modularity and reconfigurability for a low number of configurations.

[007] In summary, the execution of a modular electrical supply architecture capable of distributing the conversion capacity in functions of the instantaneous electrical power needs of different electrical loads presents numerous benefits. But it was found that the parallel association of converters is, in practice, delicate due to the recirculation currents generated between the converters. This problem still needs to be solved, as the immediate solution consisting of having an interphase inductor between converters associated in parallel does not allow sufficient modularity. The invention aims at a modular and reconfigurable power conversion device overcoming these difficulties.

[008] To this end, the invention aims to provide a device for supplying various loads from an electrical energy supply network, comprising several converters, powered by the network, ensuring the conversion and supply of electrical energy of at least one charge. The device comprises a control element configured to associate several converters in parallel to supply at least one load, in response to a power demand of at least one load. Each of the converters comprises distributed means for limiting the recirculation currents generated by the parallel association of the various converters.

[009] Advantageously, the distributed means of each of the converters are configured to generate a high zero-sequence impedance preventing creation of recirculation current between the associated converters in parallel.

[010] Advantageously, each of the converters delivers electrical energy to at least one load in phases N1. The means distributed of each of the converters comprise a zero-sequence transformer coupling the phases N1, configured to generate a high zero-sequence impedance allowing to prevent, for each phase, the creation of high frequency recirculation between the converters.

[011] Advantageously, each of the converters delivers electrical energy to at least one load in phases N1, and the distributed means of each of the converters comprise for each of the phases N1, a differential mode inductance, configured to generate an impedance of high zero sequence allowing to prevent, for each phase, the creation of high frequency recirculation current between the converters.

[012] Advantageously, each of the converters comprises filtering means associated with the transformer of each of the phases N1.

[013] Advantageously, each of the converters delivers three-phase alternating electrical energy to at least one load.

[014] Advantageously, each of the converters is supplied with electrical energy by the supply network in N2 phases, and the distributed means of each of the converters comprises a transformer coupling the N2 phases, configured to generate a high zero-sequence impedance allowing to prevent , for each phase, the creation of high frequency recirculation current between the converters.

[015] Advantageously, each of the converters comprises filtering means associated with the transformer coupling the N2 phases.

[016] Advantageously, each of the converters is supplied in electrical energy by a continuous electrical network.

[017] Advantageously, the distributed means of each of the converters comprises a zero sequence regulator configured to control the common mode voltage of each of the converters in order to nullify the common mode current of the N1 phases, allowing to prevent the creation of low frequency recirculation current between converters.

[018] Advantageously, the distributed means of each of the converters are configured to nullify the common mode voltage differences between the associated converters in parallel.

[019] Advantageously, the converters deliver energy to at least one load in the N1 phases, and the distributed means of each of the converters comprise a conversion element complementary to the conversion means in the N1 phases and a filtering element, allowing a filtration active common mode voltage in each of the converters (16).

[020] The invention will be better understood and other advantages will appear on reading the detailed description of the embodiments given by way of example in the following figures. - Figure 1, already presented, represents an example of the modular and reconfigurable power supply architecture considered in the known state of the art; - Figure 2, already presented, illustrates the principle of interlacing between two converters associated in parallel; - Figure 3, already presented, illustrates the principle of using an interphase inductor for the parallel association of two converters; - Figure 4 illustrates the principle of generating recirculation currents linked to the association of parallel converters; - figures 5a and 5b represent two embodiments of an electrical supply device comprising means for limiting high frequency recirculation currents; Figure 6 represents a third embodiment of an electrical supply device comprising means for limiting high frequency recirculation currents; Figure 7 represents a fourth embodiment of an electrical supply device comprising complementary means for limiting low frequency recirculation currents; Figure 8 represents a fifth embodiment of an electrical supply device comprising means for canceling out common mode voltage differences; - Figure 9 represents the parallel association of N converters to the medium of a power supply device according to the first embodiment; - Figure 10 represents the functional architecture of a control unit that can be executed in the supply device; - Figure 11 represents an embodiment of a low-level control module for the control unit; - Figures 12a and 12b represent an embodiment of an intermediate control module of the command unit; Figure 13 represents an embodiment of a control module system control module; - Figure 14 represents a common mode transformer with a three-legged circuit; - Figure 15 represents a compact and monoblock magnetic structure integrating the components of a zero sequence transformer with common mode and differential mode filtration by an inverter / rectifier type converter; - Figure 16 represents an example of implementation of a compact monoblock magnetic assembly bringing together the necessary magnetic elements for common and differential mode filtration for a high-power converter of the three-phase inverter / rectifier type;

[021] For clarity, the same elements will contain the same references in the different figures.

[022] Figures 4 to 8 describe various embodiments of the invention, in the most common case of a supply of the converters 16 by a continuous supply network. Loads 14 are powered by three-phase alternating voltages. That is, for each of the converters 16, input 20 comprises two poles and output 21 comprises three phases. This choice corresponds to the most widespread case in the aeronautical field. This choice, however, is not limiting of the present invention. She also considers executing the invention in different configurations, in type of current/voltage and in number of phases, both at the input and at the output of the converters. In this sense, figures 9 and 10 describe the case of converters associated in parallel for the load supply to the N1 phases from an electrical energy supply network to the N2 phases.

[023] Figure 4 illustrates the principle of generating circulating currents linked to the association of parallel converters. The paralleling and/or interlacing of several converters is likely to generate two types of recirculation currents: - high frequency recirculation currents, generated by the interaction of the cuts of the different converters; and - low frequency recirculation currents, due to differences in the command parameters of the different converters.

[024] It is possible to mold this phenomenon through a molding called "switching functions" represented in figure 4. In this case where two converters are associated in parallel, the molding shows that the recirculation current is a common mode current, where in each converter, the sum of the phase currents ia+ib+i+c, is not null but equal to a current i0 circulating between the two converters. Current i0 is generated because of the common mode voltage intervals between the two converters for each converter cut-off period.

[025] To limit the recirculation currents, a first theoretical approach is to create a strong zero-sequence impedance between the converters. This high impedance makes it possible to limit the temporary evolution of the di/dt current resulting from the differences in common mode voltages of the converters. This approach can, for example, be implemented by adding an interphase inductor between converters as described above. The placement of an interphase inductor between each phase of the converters allows forcing the phase current pairs (ia, ia’), (ib, ib’) and (ic, ic’) to values close to zero. This represents the creation of a strong zero-sequence impedance that prevents the creation of an io current between the converters. However, the inconveniences in terms of modularity of this solution with an interphase inductor external to the converters must be pointed out.

[026] A second theoretical approach is to nullify the common mode voltage differences between converters placed in parallel. As will be described in the following figures, the device according to the invention makes it possible to limit the recirculation currents by means of the first and/or second theoretical approach, all overcoming the limits of existing solutions.

[027] Figure 5 represents a first embodiment of a power supply device comprising means to limit high frequency recirculation currents. In this example, two converters 16, supplied with electrical energy by the same continuous network 25, are subjected, by a control unit 17, to a load 14. The two converters 16 ensure the conversion and supply of the load 14 to three-phase alternating voltage . Each converter 16 comprises, between an input 20 and an output 21, means 30 for filtering the energy supplied by the network 25, means for converting DC/AC 31, and means for filtering 32 for the alternate signals generated by the means for converting 31. of filtration 30 and 32 and the conversion means 31 are the classic components well known to those skilled in the art. Its operation is not described in detail here.

[028] Each of the converters 16 further comprises distributed means 33a configured to generate a high zero sequence impedance preventing the creation of recirculation current between the associated converters in parallel. In this example, the distributed means 33a comprises a zero-sequence transformer 34a linking the conversion means 31 to the filtering means 32. In each converter, and independently of the other converters, the zero-sequence transformer 34a couples the three phases of the converter forcing the sum Ia+ib+ic=i0 of each converter for values close to zero. At the system level, this corresponds to generating a high zero-sequence impedance, allowing to prevent the creation of high frequency recirculation current between the converters.

[029] The 34a zero-sequence transformers, also called zero-sequence blocking transformers, can be implemented using a common-mode inductance-type magnetic structure.

[030] The high zero sequence impedance is generated using a magnetic body 200 simultaneously coupling the three output phases of each power module, as shown in figure 14. This coupling is governed by the magnetic equation FluxA+FluxB+FluxC= Lseq_zero* (la+lb+lc). The Lseq_zero parameter is determined by the physical geometry of the magnetic body and the number of turns of the windings. The objective is, by designing the geometry and the number of turns of the windings, to maximize Lseq_zero in order to minimize the recirculation currents.

[031] The realization of the magnetic core can be made, for example, from a toroid type core with three windings. It is also possible to realize the common-mode transformer with a three-legged circuit in which the three windings are positioned on the center leg. Finally, as illustrated in figure 14, a two-legged circuit can be used with the three windings positioned on one leg.

[032] Additionally, the application of magnetic integration techniques allows to determine a compact and monoblock magnetic structure 201 integrating the zero sequence transformer components with common mode and differential mode filtration for an inverter / rectifier type converter. The proposed solution allows to integrate the three differential-mode inductances and the common-mode inductance and the zero-sequence transformers in a compact monoblock magnetic structure comprising 4 elements and three windings. This solution allows the grouping of the magnetic core and the windings between the differential mode inductances and the common mode inductance, as shown in Figure 15.

[033] The integration of the set of elements necessary for zero-sequence transformers, differential mode filtration in a monoblock magnetic set allows to optimize the weights and volume by grouping the magnetic core between the three inductances. In addition, the integration of a monobloc set also makes it possible to improve weight and volume thanks to the reduction of accessories needed for the storage and interconnection of the magnetic elements.

[034] The monoblock magnetic assembly consists of a magnetic core with four legs. Three of the legs with their associated windings play the role of the differential inductances for the considered phase. A fourth leg without a winding plays the role of common-mode inductance. The magnetic monoblock assembly is identical in terms of the magnetic equation to the zero-sequence transformer, the three single-phase inductances, and the common-mode inductance, as illustrated by the reluctance circuit models in Figure 15.

[035] Figure 16 illustrates an example of implementation of a compact monoblock magnetic assembly 202 bringing together the necessary magnetic elements for common mode and differential mode filtration for a high-power converter of the three-phase inverter / rectifier type. An implementation of the monoblock compact magnetic element can use for the differential legs a high induction material with a discrete divided air gap in order to minimize losses at high frequencies. It is also possible to implement a distributed air gap by adapting the material used. Common-mode inductance is implemented by adding a fourth leg to the three-phase differential block. The common mode leg can be implemented with the help of high magnetic permeability materials such as nanocrystalline materials.

[036] That is, this first embodiment is based on the first theoretical approach of reducing recirculation currents described in figure 4. The zero-sequence transformer 34a generates a zero-sequence impedance coupling for each converter, each of the phases through of the magnetic body. The generated impedance prevents the creation of a recirculation mode current by the common mode voltage difference between the converters. These transformers are sized similarly to a common-mode filtration inductor. Simple and mastered technological solutions, such as torus or E-shaped magnetic cores in nanocrystalline materials, can be implemented to obtain strong impedance values allowing to limit the recirculation currents to relatively low values.

[037] Figure 5b represents a second embodiment of a power supply device comprising means to limit recirculation currents of high frequencies. As in the previous embodiment, two converters 16, supplied with electrical energy by the same continuous network 25, are subjected, by a control unit 17, to a load 14. The two converters 16 ensure the conversion and supply of the load. 14 in three-phase alternating voltage. Each converter 16 comprises, between an input 20 and an output 21, means 30 for filtering the energy supplied by the network 25, means for converting DC/AC 31 and means for filtering 32 for the alternating signals generated by the means for converting 31.

[038] Each of the converters 16 further comprises distributed means 33b configured to generate a high zero-sequence impedance preventing the creation of recirculation current between the associated converters in parallel. In this example, the distributed means 33b comprises for each of the phases, a differential mode inductance, i.e. a three-phase differential inductance 34b linking the conversion means 31 to the filtering means 32. The differential mode inductances are perceived by the differential component and the common-mode composite of the current. Depending on their value, the differential mode inductances in each converter reduce the sum ia+ib+ic=i0 of each converter to values close to zero. At the system level, they contribute to generating a high zero-sequence impedance, allowing to prevent the creation of high frequency recirculation current between the converters.

[039] Thus, this second embodiment is also based on the first theoretical approach of reducing recirculation currents described in Figure 14. Differential mode inductances generate a zero-sequence impedance. These inductances are sized similarly to a differential mode filtration inductor. Its sizing can be the object of a system-level optimization. A strong differential-mode inductance value on each module allows you to reduce the common-mode current to a low value. But a strong differential mode inductance value is penalizing in terms of weights and volume, despite the new magnetic materials. On the contrary, a lower value of differential mode inductance increases the value of the recirculation current and therefore the ripple and peak currents in the phases of the conversion means. It can also be said that an increased current in the switches of the conversion means is detrimental to their functioning. Thus, the optimization of the inductance value in a differential mode results from a compromise between the value of the peak currents per phase, the recirculation currents and the setting of the switches. Typically, an optimized value of the differential mode inductance allows to obtain ripple compatible with the switch setting, minimizing switching losses by performing a smooth switching, no switching loss at switch startup and no switching loss for blocking diodes.

[040] It is interesting to note that to respect the EMI specifications, it is necessary to implement in the converters 16 a differential mode filtering. Differential mode filtration is equivalent to differential mode inductors. A further optimization is therefore the integration in each of the converters of differential mode inductors to limit the recirculation current with the required differential mode inductors according to EMI specifications. This allows coupling the means to limit the recirculation currents and differential mode inductances necessary for EMI requirements through a single magnetic component. In other words, an appropriate dimensioning of the inductances in a differential mode makes it possible to integrate the function of the means of limiting the recirculation currents, advantageously allowing to limit the overall filtration weights, without implying the implementation of additional components.

[041] Figure 6 represents a second embodiment of an electrical supply device according to the invention. As before, two converters 16, supplied by the continuous network 25 are subjected by a control unit (not shown in this figure) to a load 14. Each converter 16 comprises, between an input 20 and an output 21, energy filtering means 30 provided by the network 25, means for converting 31 and means for filtering 32 of the alternate signals generated by means for converting 31.

[042] Each of the converters 16 further comprises distributed means 43 configured to generate a high zero sequence impedance preventing the creation of recirculation current between the associated converters in parallel. In this example, the distributed means 43 are arranged at the input 20 of the converters 16 and comprise for each polarity of the continuous network 25, a transformer 44 linking the input 20 to the conversion means 31.

[043] That is, this second embodiment places a zero sequence blocking mode transformer in each converter. Each transformer creates a zero-sequence impedance by coupling the two input polarities of each converter through the transformer's magnetic body. As before, the generated impedance prevents the creation of a recirculation mode current by the common mode voltage difference between the converters. The already mentioned technological solutions, such as toroidal or E-shaped magnetic cores in nanocrystalline type materials can be advantageously implemented.

[044] It is interesting to note that to comply with EMI specifications, the converter system needs to implement a common mode filtering. Typically, this common-mode filtering corresponds to a common-mode inductor linking the three output phases of the converters. A further optimization is therefore the integration in each of the modules of the zero-sequence blocking transformers with the common-mode inductance necessary for the common-mode cut-off noise filtrations. This allows the implementation of zero-sequence blocking transformer and common-mode inductance in a single magnetic element. Proper sizing of zero-sequence blocking transformers therefore allows to integrate the common-mode filtration function, thus minimizing the overall filtration weights. The integration in each of the modules of these common mode recirculation and filtration current blocking devices allows not to add the additional element for the parallelization of the modules.

[045] Figure 7 represents a fourth embodiment of a power supply device comprising complementary means to limit low frequency recirculation currents. The first three embodiments described in figures 5a, 5b and 6 respectively, implement the means distributed in each of the converters capable of limiting high frequency recirculation currents. The fourth embodiment described by figure 7 comprises distributed means similar to the first embodiment, comprising a zero-sequence transformer 34 allowing to limit the recirculation currents of high frequencies. The fourth embodiment is intended to limit recirculation currents at low frequencies as well. For this purpose, it combines with zero sequence blocking transformers limiting recirculation currents at high frequencies, a zero sequence regulator to limit recirculation currents at low frequencies. The zero-sequence regulator can be associated with transformers implemented in input filters or output filters. In figure 7, each converter 16 comprises means 30 for filtering the energy supplied by the continuous network 25, means for converting 31 and means for filtering 32 for the alternate signals generated by the means for converting 31. Each converter further comprises distributed means 50 configured to generate a high zero-sequence impedance preventing the creation of recirculation current between the associated converters in parallel. The distributed means 50 comprise on one side a zero-sequence transformer linking the conversion means 31 to the filtering means 32, and on the other side a zero-sequence regulator 51. The zero-sequence regulator 51 comprises means for measuring the phase currents ia, ib and ic at the output of the transformers 34, calculate the common mode current ia+ib+ic, and control the conversion means 31 with instructions for regulating a zero common mode current. That is, the regulator 51 allows to reduce the low frequency recirculation currents by setting the low frequency compound of the recirculation current to zero, by controlling the common mode voltage for the PWM instructions of the conversion elements 31. A possibility of variation of The control for the common mode voltage is the distribution of the zero vector of the PWM instructions between the (1,1,1) vector and the (0,0,0) vector. Vector time (1,1,1) can be equal to vector time (0,0,0). For a larger data of the zero vector, the zero sequence controller can act on the distribution between the vector (1,1,1) and the vector (0,0,0) and control the common mode voltage at the converter output for control the low frequency recirculation current at zero. Each converter thus independently controls its recirculation current, allowing, at the level of the supply device, to cancel the set of recirculation currents without using a common corrector. The principle of these zero-sequence regulators distributed in each converter makes it possible to nullify the low frequency recirculation currents. This regulator can be implemented in different ways depending on the applications considered and the topologies of the converters.

[046] As in the previous figures, each converter 16 comprises filtering means 30 of the energy supplied by the continuous network 25, conversion means 31 and filtering means 32 of alternating three-phase signals generated by the conversion means 31. Each converter further comprises distributed means 60 to limit the recirculation currents generated by the parallel association of several converters. The distributed means 60 comprise an additional converting element 61, integrated with the converting means 31, and a filtering element 62. These distributed means 60 constitute a supplementary cutting arm, associated with the three cutting arms of each of the stages. The distributed means 60 are controlled, in particular the cyclic relation opening command, or PWM, of the conversion element 61, so as to nullify the common mode voltage of the three phases. That is, the fourth arm allows an adapted control in PWM to control the common mode voltage of each converter. It is possible to establish the common mode voltage of each converter, with the instruction to regulate a zero recirculation current.

[047] Figure 8 describes the principle of active filtering of common mode voltage in the case of an electrical conversion in three phases. This example is not limiting, it more broadly considers distributed means 60 comprising a supplementary conversion element integrated into the electrical conversion means in N1 phases.

[048] Figure 9 represents the parallel association of N converters through a power supply device according to the invention. In most cases, converters powered by a continuous network and delivering three-phase alternating voltages do not constitute a limitation to the present invention. As represented in figure 9, the supply device can comprise N converters fed by an electrical energy network in N2 phases, ensuring the conversion and supply of loads in N1 phases. Different types of conversion media 31 can be used (AC/AC, DC/AC, AC/DC, DC/DC).

[049] Figure 10 represents the functional architecture of a control unit implemented in the feeding device. It can be stated that the supply device according to the invention comprises a control element 17 capable of distributing, in real time, one or several converters to a load. A privileged way of carrying out this command body responsible for the allocation of converters and their control will be described. The control unit established by the present invention ensures the control of the supply device as a whole for various functions. In particular, it generates the parallel association of converters, the control of load command algorithms, the interweaving between the converters or even the control of the control algorithm specific to the converters independently of the loads.

[050] The command organ can be divided into several modules depending on functional and temporal criteria. Among the functional criteria, the architecture of the relevant control unit takes into account, in particular, the type of conversion carried out, the internal structure of the converter, the load control algorithm, or the possible reconfigurations of the supply device. Among the temporal criteria, it takes into account the time constants of the protection functions, the electromechanical time constants, the passing bands of the control algorithms, and the sampling and cutting frequencies.

[051] As depicted in Figure 10, a control unit 17 comprising, in more than one step of power 100, three control modules is contemplated: a low-level control module 101, an intermediate control module 102 and a module system control 103. The principle and the ways in which these control modules are carried out are described in the following figures.

[052] Figure 11 represents an embodiment of a low-level control module for the control unit. This module 101 is in charge of fast tasks dedicated to electrical energy conversion, such as associated protection tasks. A low-level control module is associated with each device's converter. It is preferably implemented in an electronic device integrated in the converter, for example with the power stage. Alternatively, the converters' low-level control modules can be mounted in a central electronic device. The low level control module 101 associated with a converter is independent of electrical load.

[053] The compensation command is designed to take on the quick and oriented tasks in energy conversion and associated protection. This command is independent of the load and its dedicated control algorithms. The compensation command is an integral part of the conversion elements making these elements intelligent and able to interface with a higher level application layer. The compensation command also generates the inter- and intra-module interactions due to the interweaving and paralleling of such modules. The compensation command includes the low frequency recirculation current control elements with an integrated zero sequence current controller acting on the PWM command to keep the low frequency recirculation current at zero.

[054] The low-level control module 101 comprises for each of the converters means for regulating the currents Id, Iq and I0. The I0 current control ensures that the recirculation current is set to zero when acting on the PWM command of the converter. The control of Id and Iq currents ensures the establishment of the output currents of each of the converters on the instruction values transmitted by the intermediate control module in a master/slave relationship. This particular configuration allows a balance of currents between the associated converters in parallel.

[055] In the case where the converters comprise means to limit the recirculation currents of low frequencies, by means of a zero sequence regulator 51 described by figure 7, the low level control module 101 ensures the PWM command of the regulator. In the case where the converters comprise common-mode voltage active filtering means 60, by means of a supplementary converter arm 61 described by figure 8, the low-level control module 101 ensures command of the supplementary converter arm.

[056] Low level control is unique to each drive and is independent of system control and intermediate control parameters.

[057] As depicted in figure 11, the compensation command is in charge of the control tasks dedicated to the conversion such as: • PWM generation and modulation • Gate drivers • Current mode control • Over current and over temperature protection • Control of low frequency recirculation currents • Control of high frequency recirculation currents for active solution. • ...

[058] The incorporation of this command in the conversion elements makes them generic and decouples the tasks linked to the conversion from the tasks linked to the application or system control. This enhances the possibility of creating a modular system and an open platform based on application-independent generic conversion modules.

[059] Figures 12a and 12b represent an embodiment of an intermediate control module of the command unit. This module 102 is in charge of the tasks dedicated to the control of electrical loads 14, the tasks of interlacing and paralleling the converters. The intermediate control module 102 drives the converters' low-level control modules 101 in a master/slave relationship. This relationship is, for example, illustrated by figure 12a which represents an intermediate control module ensuring command of the low level control modules 101 of two converters placed in parallel for the supply of an electrical load 14. The intermediate control 102 transmits to the converters the values of control instructions adapted to the allocation between converters and loads. It transmits, for example, instructions containing the type of conversion to be carried out, the cutoff frequency, the type of PWM or even instructions on interlacing and paralleling in real time.

[060] The intermediate control module is independent of the power conversion tasks supported by the low-level control modules. It only secures the command. By way of example, sensorless command algorithms for compressor, hydraulic pump or start, or even bus regulation algorithms (eg 400Hz CF, or 28 Vdc) or battery charge algorithms will be implemented in the intermediate control module.

[061] The application brain is completely independent and dissociated from the energy conversion and conditioning tasks undertaken by the compensation commands.

[062] As depicted in Figure 12b, the intermediate control module is configured to ensure simultaneous control of multiple electrical loads. For each of the electrical loads, an intermediate level control guarantees the command of the low level control modules of each of the converters placed in parallel to supply the load.

[063] It is also considered by the present invention to execute several intermediate control modules to ensure a redundancy of the associated command. The intermediate control module can be implemented in an independent electronic module with redundancy.

[064] Figure 13 represents an embodiment of a control system control module. This module 103 is in charge of supervision and inspection tasks. The system 103 control module ensures real-time allocation of converters to electrical loads. It further coordinates the command of the 102 intermediate control modules and defines their instruction parameters. The system control module 103 interfaces with the aircraft, and reconfigures the power supply device depending on the information transmitted by the aircraft. It also generates protection devices and the fault resolution of the intermediate control modules 102.

[065] It is considered to run several system control modules to ensure a redundancy of the associated command. The system control module can be implemented in an independent electronic module with redundancy. It can also be implemented in an existing redundant control unit, such as the BPCU or any other redundant control unit present in the aircraft.

[066] This particular functional architecture of the command organ is advantageous as it allows for a modular electrical architecture and an open development platform. Low-level tasks are hidden and decoupled from higher hierarchical level tasks. The system is fully modular and reconfigurable from converters independent of electrical loads and the electricity supply network. This configuration allows optimizing the electrical power installed in the aircraft by real-time allocation of the sharing of conversion resources between the N loads. This configuration also makes it possible to optimize the filtering included in the converters by their entanglement at the system level, on the source side and on the load side.

[067] This modular architecture constitutes an open development platform, which allows the integration of elements from different industrial partners without particular difficulty of interfacing with the rest of the device.

[068] The proposed architecture is a generic solution and a modular platform allowing the integration of multiple functions sharing the same conversion resources. This architecture combines multiple functions in a power conversion center allowing to reduce weight and costs by eliminating the need for converters dedicated to different applications. Figure 13 illustrates an enclosure integrating four applications (A, B, C, D) into the application brain.

[069] The proposed architecture is based on an open architecture allowing the integration of third-party applications without intellectual property or interface difficulties. It allows the integration of functions developed by different vendors within the same cabinet.

[070] The distributed and divided control architecture, combined with high computation integrity, allows a safe operation of different functions in the system with an open architecture. Each partner receives a standard power box, a set of development tools, and a set of development rules for developing their control algorithms and software code. When the partner finishes developing the control algorithm and software, the software is loaded into the application brain of the cabinet without compatibility or intellectual property issues.

Claims (11)

1. Device for feeding several loads (14) from an electrical energy supply network (25), comprising several converters (16), fed into electrical energy by the network (25), ensuring the conversion and feeding into energy electrical power of at least one load (14) CHARACTERIZED by the fact that it comprises a control unit (17) configured to associate several converters (16) in parallel to supply at least one load (14), in response to a power requirement of at least a load (14), and in which each of the converters (16) comprises distributed means (33, 43, 50, 60) for limiting the recirculation currents generated by the parallel association of many converters (16), the distributed means ( 33, 43, 50) of each of the converters (16) being configured to generate a high zero sequence impedance preventing creation of recirculation current between the associated converters (16) in parallel. 2. Device according to claim 1, CHARACTERIZED by the fact that each of the converters (16) delivers electrical energy to at least one load in Phases N1, and by the fact that the distributed means (33a) of each of the Converters (16) comprise a zero sequence transformer (34a) coupling the phases N1, configured to generate a high zero sequence impedance allowing to prevent, for each phase, the creation of high frequency recirculation current between the converters (16). 3. Device according to claim 1, CHARACTERIZED by the fact that each of the converters (16) delivering electrical energy to at least one load in Phases N1, and by the fact that the distributed means (33b) of each of the converters (16) comprising for each of Phases N1 a differential mode inductance (34b), configured to generate a high zero sequence impedance allowing to prevent, for each phase, the creation of high frequency recirculation current between the converters (16 ). 4. Device according to claim 2, CHARACTERIZED by the fact that each of the converters (16) comprises filtering means (32) associated with the transformers (34) of each of Phases N1. 5. Device according to claim 2 or 3, characterized by the fact that each of the converters (16) delivers three-phase alternative electrical energy to at least one load (14). 6. Device according to any one of claims 1 to 5, CHARACTERIZED by the fact that each of the converters (16) is supplied with electrical energy by the supply network (25) in Phases N2, and by the fact that the distributed means ( 43) of each of the converters (16) comprises a transformer (44) coupling the Phases N2, configured to generate a zero sequence impedance allowing to prevent, for each phase, the creation of high frequency recirculation current between the converters. 7. Device according to claim 6, CHARACTERIZED by the fact that each of the converters (16) comprises filtering means (30) associated with the transformer (44) coupling the Phases N2. 8. Device according to claims 6 or 7, CHARACTERIZED by the fact that each of the converters (16) is supplied with electrical energy by a continuous supply network (25). 9. Device according to any one of claims 2 to 5, CHARACTERIZED by the fact that the distributed means (50) of each of the converters (16) comprises a zero sequence regulator (50) configured to reduce the common mode voltage from each of the converters (16) in order to cancel the common mode current of Phases N1, allowing to prevent the creation of low frequency recirculation current between the converters (16). 10. Device according to claim 1, CHARACTERIZED by the fact that the distributed means (60) of each of the converters (16) are configured to nullify the common mode voltage differences between the converters (16) associated in parallel. 11. Device according to claim 10, CHARACTERIZED by the fact that the converters deliver energy to at least one load in Phases N1, and by the fact that the distributed means (60) of each of the converters (16) comprises an element converter (61) complementary to the conversion means (31) in Phases N1 and a filtering element (62) allowing an active common-mode voltage filtering in each of the converters (16).

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